Flexoelectric effect is the response of electric polarization to the mechanical strain gradient. At the nano-scale, where large strain gradients are expected, the flexoelectric effect becomes appreciable and may substitute piezoelectric effect in centrosymmetric materials. These features make flexoelectricity of growing interest during the last decade. At the same time, the available theoretica...

The flexoelectric effect for pear-shaped molecules was studied within NPT Monte Carlo simulations. The asymmetric molecules were modelled by a heterogenic two-site pair potential consisting of rigidly connected Gay-Berne and Lennard-Jones particles, thus giving rise to a steric dipolar moment. The simulation data for order parameters and pair correlation functions were used within a density fun...

A centrosymmetric stress cannot induce a polar response in centric materials; piezoelectricity is, for example, possible only in non-centrosymmetric structures. An exception is metamaterials with shape asymmetry, which may be polarized by stress even when the material is centric. In this case the mechanism is flexoelectricity, which relates polarization to a strain gradient. The flexoelectric r...

The stability of the equilibrium configurations of a nematic liquid crystal confined between two coaxial cylinders is analysed when a radial electric field is applied and the flexoelectric effect is taken into account. The threshold for perturbations depending only on the radius r in the cylindrical coordinate system and strong boundary conditions is studied. A new type of orientational transit...

The flexoelectric polarization (Pf) of four bent-core nematic liquid crystals (LCs) has been measured using the pyroelectric effect. Hybrid aligned nematic cells are fabricated for measuring the pyroelectric response over the entire range of the nematic phase. It is found that the magnitude of flexoelectric polarization Pf and the sum of the flexoelectric coefficients |e1+e3| for the bent-core ...

We report theoretical analysis of the electronic flexoelectric effect associated with nanostructures of sp(2) carbon (curved graphene). Through the density functional theory calculations, we establish the universality of the linear dependence of flexoelectric atomic dipole moments on local curvature in various carbon networks (carbon nanotubes, fullerenes with high and low symmetry, and nanocon...

Piezoelectricity—the coupling between strain and electrical polarization, allowed 2 Zubko, Catalan, Tagantsev by symmetry in a restricted class of materials—is at the heart of many devices that permeate our daily life. Since its discovery in the 1880’s by Pierre and Jacques Curie, the piezoelectric effect has found use in everything from submarine sonars to cigarette lighters. By contrast, flex...

We report experimental and theoretical results on the flexoelectric instability and crossover between flexoelectric domains and electro-convection in a hybrid aligned nematic MBBA under d.c. voltage. At threshold a spatially periodic flexoelectric deformation in the form of longitudinal domains (along the planar director) was observed. With increasing voltage the director deviation out of the i...